I know this post is old, but thought I would throw in my thoughts in case anyone else wanted to chime in.
I have pics of a goal person that I ask myself, "Would this person want to fuck me given how my body is now?" And I set goal dates (holidays, birthdays, end of year) and imagine what I want to look like on those dates and while I workout all aspects of my body, I tend to concentrate on the key areas. Like my glutes. I particularly love working out my glutes. Got to have the kind of ass that looks good in jeans, and makes men want to have in their hands as they are fucking you from behind! If you can find a buddy to hold you accountable, that's a great motivator as well. Send them a "before pic" and make them a promise that in X days/months, you will send them an even better pic.